Add in-app help page with user manual (Romanian)

Adds a /help page served from the dashboard navigation, containing the full
Romanian user manual for operators: dashboard, playlist management, adding
media, removing files from playlists, player management, and the advanced
edited-media view.

Implementation notes
- Manual is pre-rendered to HTML with pandoc and shipped as a static asset
  (app/static/help/_manual_body.html) rather than parsed at runtime. This
  keeps the container free of a Markdown dependency and makes the page render
  identically regardless of what is installed.
- /help is login-protected; the sidebar table of contents is derived from the
  level-2 headings at request time.
- Screenshots are served from app/static/help/screenshots/ (32 images).
- Regenerate after editing the manual:
    documentatie/convert_help_page.sh
    docker compose up -d --build

Also adds
- backup_players_playlists.sh / restore_database.sh for DB backup and restore.
- .gitignore rules so local database backups (real production data), generated
  .docx files and duplicate screenshot copies are never committed.

documentatie/convert_help_page.sh

@@ -0,0 +1,93 @@
+#!/bin/bash
+# ============================================================================
+# convert_help_page.sh - Regenerates the in-app help page content
+# ----------------------------------------------------------------------------
+# Converts documentatie/Manual-Utilizare-DigiServer.md into the HTML fragment
+# that the Flask app serves at /help, and refreshes the screenshot copies.
+#
+# Run this whenever the manual is edited, then rebuild the image:
+#   ./documentatie/convert_help_page.sh
+#   cd .. && docker compose up -d --build
+# ============================================================================
+set -euo pipefail
+
+PROJECT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+SRC_MD="$PROJECT_DIR/documentatie/Manual-Utilizare-DigiServer.md"
+SRC_IMG_DIR="$PROJECT_DIR/documentatie/screenshots"
+DEST_DIR="$PROJECT_DIR/app/static/help"
+DEST_IMG_DIR="$DEST_DIR/screenshots"
+DEST_HTML="$DEST_DIR/_manual_body.html"
+
+echo "============================================================"
+echo " Regenerare pagina Ajutor (/help)"
+echo "============================================================"
+echo
+
+# ---------------------------------------------------------------------------
+# Checks
+# ---------------------------------------------------------------------------
+if ! command -v pandoc &> /dev/null; then
+    echo "✗ Pandoc nu este instalat."
+    echo "  Instalati cu: sudo apt-get install -y pandoc"
+    exit 1
+fi
+if [ ! -f "$SRC_MD" ]; then
+    echo "✗ Nu am gasit manualul: $SRC_MD"
+    exit 1
+fi
+
+mkdir -p "$DEST_IMG_DIR"
+
+# ---------------------------------------------------------------------------
+# 1. Convert Markdown -> HTML fragment
+# ---------------------------------------------------------------------------
+echo "[1/3] Conversie Markdown -> HTML..."
+pandoc "$SRC_MD" \
+    -t html5 \
+    --no-highlight \
+    --wrap=none \
+    -o "$DEST_HTML"
+echo "  ✓ $(basename "$DEST_HTML")"
+
+# ---------------------------------------------------------------------------
+# 2. Copy screenshots and rewrite their paths for Flask's static route
+# ---------------------------------------------------------------------------
+echo
+echo "[2/3] Copiere capturi de ecran si rescriere cai..."
+cp "$SRC_IMG_DIR"/*.png "$DEST_IMG_DIR"/ 2>/dev/null || {
+    echo "  ⚠ Nicio captura gasita in $SRC_IMG_DIR"
+}
+COUNT=$(ls -1 "$DEST_IMG_DIR"/*.png 2>/dev/null | wc -l)
+echo "  ✓ $COUNT capturi copiate"
+
+# Markdown references images as "screenshots/x.png"; the app serves them from
+# /static/help/screenshots/, so the prefix has to be made explicit.
+sed -i 's|src="screenshots/|src="/static/help/screenshots/|g' "$DEST_HTML"
+REFS=$(grep -c '/static/help/screenshots/' "$DEST_HTML" || true)
+echo "  ✓ $REFS referinte de imagini rescrise"
+
+# ---------------------------------------------------------------------------
+# 3. Sanity check: every referenced image must exist
+# ---------------------------------------------------------------------------
+echo
+echo "[3/3] Verificare consistenta..."
+MISSING=0
+while IFS= read -r ref; do
+    [ -z "$ref" ] && continue
+    if [ ! -f "$DEST_IMG_DIR/$(basename "$ref")" ]; then
+        echo "  ✗ lipsa: $ref"
+        MISSING=$((MISSING + 1))
+    fi
+done < <(grep -oE '/static/help/screenshots/[^"]+' "$DEST_HTML" | sort -u || true)
+
+if [ "$MISSING" -eq 0 ]; then
+    echo "  ✓ toate imaginile referite exista"
+else
+    echo "  ⚠ $MISSING imagini lipsa"
+fi
+
+echo
+echo "============================================================"
+echo " Gata. Rebuild imaginea pentru a aplica modificarile:"
+echo "   cd $PROJECT_DIR && docker compose up -d --build"
+echo "============================================================"